Monorail bogies for supporting monorail cars are known in the art and are used in many monorail car assemblies for supporting the running wheels and guide wheels beneath the monorail cars.
Many monorail bogies support load bearing wheels that travel on the upper surface of the monorail track and guide wheels that travel along the side surfaces of the monorail track, and that provide lateral support for the monorail car. A common problem with many such monorail bogies is that as the monorail bogies travel over a curved section of track, there is a significant increase in the load on certain guide wheels of the monorail bogie. In most cases the monorail bogie will have four guide wheels that travel along the side surfaces of the monorail track; namely an outboard inner guide wheel, an outboard outer guide wheel, an inboard inner guide wheel and an inboard outer guide wheel. As used herein, the term “inboard” refers to the side of the monorail bogie 14 that is closer to the centre of the monorail car body 12 and the term “outboard” refers to the side of the monorail bogie 14 that is closer to the end of the monorail car body 12. In addition, the term “inner guide wheel” refers to the wheels on the interior side of a curve and the term “outer guide wheel” refers to the wheels on the outer side of a curve.
When a monorail bogie travels over a curved section of track, there is an increase in the load on the outboard inner guide wheel. This increase in load is generally caused as a result of a high rotational stiffness between the monorail bogie and the monorail car, which prevents the monorail bogie from being properly aligned with the monorail track during travel through a curved section of track. This misalignment results in the outboard inner guide wheels (and in some cases the inboard outer guide wheel) to be compressed against the track. This compression creates relatively high load forces on the outboard inner guide wheel (and often the inboard outer guide wheels), which can undesirably cause premature wear of the guide wheels.
In light of the above, it can be seen that there is a need in the industry for an improved monorail bogie that improves on the overall functionality of existing monorail bogies and that better distributes and reduces the load experienced by the guide wheels especially when the monorail car travels over a curved section of monorail track.